Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Using single quantum dots to probe nanowires: Lighting up plasmonic wires with nanometer accuracy

 (a) This is an optical image of the microfluidic crossed-channel device. Flow in the center control region (dashed circle) is manipulated in two dimensions by 4 external electrodes (not shown). Scale bar is 500 μm. (b) This is a schematic of the positioning and imaging technique. A single QD is driven along a trajectory close to the wire by flow control. The inset shows a microcope image of a typical nanowire with 1 μm scale bar.

Credit: JQI
(a) This is an optical image of the microfluidic crossed-channel device. Flow in the center control region (dashed circle) is manipulated in two dimensions by 4 external electrodes (not shown). Scale bar is 500 μm. (b) This is a schematic of the positioning and imaging technique. A single QD is driven along a trajectory close to the wire by flow control. The inset shows a microcope image of a typical nanowire with 1 μm scale bar.

Credit: JQI

Abstract:
Modern telecommunications happens because of fast electrons and fast photons. Can it get better? Can Moore's law---the doubling of computing power ever 18 months or so---be sustained? Can the compactness (nm-scale components) of electronics be combined with the speed of photonics? Well, one such hybrid approach is being explored at the Joint Quantum Institute (*), where scientists bring together three marvelous physics research fields: microfluidics, quantum dots, and plasmonics to probe and study optical nanostructures with spatial accuracy as fine as 12 nm.

Using single quantum dots to probe nanowires: Lighting up plasmonic wires with nanometer accuracy

College Park, MD | Posted on February 5th, 2013

PLASMONICS

When light strikes a strip of metal an electron wave can be excited in the surface. Is this "surface plasmon" a bit of light or electricity. Well, it's a bit of both. The wavelength of this electromagnetic wave is shorter and the energy density higher than that of the incoming laser light; the plasmon is thus tightly localized light constrained to propagate along the meal surface. The science of "plasmonics" has arisen to capitalize on various imaging, sensing, and processing abilities inherent in plasmons. To start with, though, one needs to know exactly what happens at that laser-excited metallic surface. That light is converted into the plasmonic wave; later the energy can be reconverted into light.

Here's where the JQI experiment comes in. The main result of the work, published February 5 in the journal Nature Communications, is to provide a map showing how the metal strip, in this case a silver wire 4 microns long and 100 nm wide, lights up.

MICROFLUIDICS AND QUANTUM DOTS

The other two chief components of the experiment, in addition to plasmonics, are microfluidics and quantum dots. Microfluidics, a relatively new science all by itself, features the movement of nanoliter volumes of fluids through channels defined on microchips, analogous to the conducting paths strung across microprocessors for carrying electrical currents. Quantum dots, nanometer-sized semiconductor balls, are tailored to possess a specified set of allowed energy states; in effect the dots are artificial atoms that can be moved around. In the JQI experiment the 10-nm-wide dots (the important cadmium-selenide layer is only 3 nm thick) float in a fluid whose flow can be controlled by varying an applied voltage. The dots are drawn up close to the nanowire as if they were mines next to a submarine.

Indeed the dot is there precisely to excite the wire. The dot is fluorescence machine---in a loose sense a nanoscopic lightbulb. Striking it with green laser light, it quickly re-emits red light (one photon at a time), and it is this radiation which excites waves in the nearby wire, which acts like an antenna. But the interaction is a two-way street; the dot's emissions will vary depending on where along the length of the wire it is; the end of the wire (like any pointy lightning rod on a barn) is where electrical fields are highest and this attracts the most emission from the dot.

A CCD camera captures light coming from the dots and from the wire. The camera qualities, the optical properties of the dot, the careful positioning of the dot, and the shape and purity of the nanowire combine to provide an image of the electric field intensity of the nanowire with 12-nm accuracy. The intensity map shows that the input red light from the quantum dot (wavelength of 620 nm) has effectively been transformed into a plasmonic wavelength of 320 nm.

Chad Ropp is a graduate student working on the project and the lead author on the paper. "Plasmonic maps have been resolved before, but the quantum mechanical interactions with a single emitter have not, and not with this degree of accuracy," said Ropp.

POSSIBLE APPLICATIONS

In an actual device, the quantum dot could be replaced by a bio-particle which could be identified through the nanowire's observed effect on particle's emissions. Or the dot-wire duo could be combined in various configurations as plasmonic equivalents of electronic circuit components. Other uses for this kind of nanowire setup might exploit the high energy density in the plasmonic state to support nonlinear effects. This could enable the nanowire-dot combination to operate as an optical transistor.

"Nanoscale imaging and spontaneous emission control with a single nano-positioned quantum dot," Chad Ropp, Zachary Cummins, Sanghee Nah, John T. Fourkas, Benjamin Shapiro, Edo Waks, Nature Communications, paper published online 5 February 2013. Chad Ropp, , 301-405-5010

####

About Joint Quantum Institute
The Joint Quantum Institute is operated jointly by the National Institute of Standards and Technology in Gaithersburg, MD and the University of Maryland in College Park.

For more information, please click here

Contacts:
Phillip F. Schewe

301-405-0989

Copyright © Joint Quantum Institute

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Prototype 'nanoneedles' generate new blood vessels in mice: Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice March 31st, 2015

Super sensitive measurement of magnetic fields March 31st, 2015

Nanomedicine pioneer Mauro Ferrari at ETH Zurich March 31st, 2015

From tobacco to cyberwood March 31st, 2015

Laboratories

Using magnetic fields to understand high-temperature superconductivity: Los Alamos explores experimental path to potential 'next theory of superconductivity' March 27th, 2015

ORNL-led team demonstrates desalination with nanoporous graphene membrane March 25th, 2015

Los Alamos Offers New Insights Into Radiation Damage Evolution: TUnderstanding defects in materials aids in performance predictions March 18th, 2015

Microfluidics/Nanofluidics

Square ice filling for a graphene sandwich March 26th, 2015

Dolomite’s microfluidics technology ideal for B cell encapsulation March 24th, 2015

Govt.-Legislation/Regulation/Funding/Policy

SUNY Poly CNSE and Title Sponsor SEFCU Name Capital Region Teams Advancing to the Final Round of the 2015 New York Business Plan Competition March 30th, 2015

Princess Margaret scientists convert microbubbles to nanoparticles: Harnessing light to advance tumor imaging, provide platform for targeted treatment March 30th, 2015

Nanoscale worms provide new route to nano-necklace structures March 29th, 2015

Designer's toolkit for dynamic DNA nanomachines: Arm-waving nanorobot signals new flexibility in DNA origami March 27th, 2015

Chip Technology

Next important step toward quantum computer: Scientists at the University of Bonn have succeeded in linking 2 different quantum systems March 30th, 2015

State-of-the-art online system unveiled to pinpoint metrology software accuracy March 27th, 2015

SUNY POLY CNSE to Host First Ever Northeast Semi Supply Conference (NESCO) Conference Will Connect New and Emerging Innovators in the Northeastern US and Canada with Industry Leaders and Strategic Investors to Discuss Future Growth Opportunities in NYS March 25th, 2015

NXP and GLOBALFOUNDRIES Announce Production of 40nm Embedded Non-Volatile Memory Technology: Co-developed technology to leverage GLOBALFOUNDRIES 40nm process technology platform March 24th, 2015

Optical computing/ Photonic computing

Building shape inspires new material discovery March 24th, 2015

Scientists invent new way to control light, critical for next gen of super fast computing March 19th, 2015

New optical materials break digital connectivity barriers: Tel Aviv University researcher discovers novel nanoscale 'metamaterial' could serve as future ultra-high-speed computing units March 19th, 2015

Mid-IR frequency combs enable high resolution spectroscopy for sensitive gas sensing March 10th, 2015

Discoveries

Prototype 'nanoneedles' generate new blood vessels in mice: Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice March 31st, 2015

Super sensitive measurement of magnetic fields March 31st, 2015

From tobacco to cyberwood March 31st, 2015

Next important step toward quantum computer: Scientists at the University of Bonn have succeeded in linking 2 different quantum systems March 30th, 2015

Announcements

Prototype 'nanoneedles' generate new blood vessels in mice: Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice March 31st, 2015

Super sensitive measurement of magnetic fields March 31st, 2015

Nanomedicine pioneer Mauro Ferrari at ETH Zurich March 31st, 2015

From tobacco to cyberwood March 31st, 2015

Quantum Dots/Rods

Next important step toward quantum computer: Scientists at the University of Bonn have succeeded in linking 2 different quantum systems March 30th, 2015

Tiny bio-robot is a germ suited-up with graphene quantum dots March 24th, 2015

Rice fine-tunes quantum dots from coal: Rice University scientists gain control of electronic, fluorescent properties of coal-based graphene March 18th, 2015

Ghent University leads large-scale European training project on quantum dots March 13th, 2015

Photonics/Optics/Lasers

Super sensitive measurement of magnetic fields March 31st, 2015

Next important step toward quantum computer: Scientists at the University of Bonn have succeeded in linking 2 different quantum systems March 30th, 2015

Solving molybdenum disulfide's 'thin' problem: Research team increases material's light emission by twelve times March 29th, 2015

A first glimpse inside a macroscopic quantum state March 28th, 2015

Alliances/Partnerships/Distributorships

NXP and GLOBALFOUNDRIES Announce Production of 40nm Embedded Non-Volatile Memory Technology: Co-developed technology to leverage GLOBALFOUNDRIES 40nm process technology platform March 24th, 2015

Young NTU Singapore spin-off clinches S$4.3 million joint venture with Chinese commercial giant March 23rd, 2015

Halas, Nordlander awarded Optical Society's R.W. Wood Prize: Rice University researchers recognized for pioneering nanophotonics March 21st, 2015

EU Funded PCATDES Project has completed its half-period with success March 19th, 2015

Research partnerships

Prototype 'nanoneedles' generate new blood vessels in mice: Scientists have developed tiny 'nanoneedles' that have successfully prompted parts of the body to generate new blood vessels, in a trial in mice March 31st, 2015

'Atomic chicken-wire' is key to faster DNA sequencing March 30th, 2015

SUNY Poly & M+W Make Major Announcement: Major Expansion To Include M+W Owned Gehrlicher Solar America Corporation That Will Create up to 400 Jobs to Develop Solar Power Plants at SUNY Poly Sites Across New York State March 26th, 2015

ORNL-led team demonstrates desalination with nanoporous graphene membrane March 25th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE